Lapping-tool



c. SCHERERJ" ""LAPPING TO0L.

, APPLICATION FILED JUNEZB. 1920.

11,382,552 Patented June 21, 1921.

INVENTOR ATTORNEY C la l'ence Scherez:

UNIT-En; STATES CLARENCE sonnimil; orcam'sajmmn DAKOTA.

.Q LAPPING-iObL.

Specification 'of'Letters Eatent. Patented J 11119 21, 1921 Application filed June 29, 1920. Serial No. 392,630.

To aZZwhom-itmay concern:

Be it known that I, CLARENCE :Scmnmn,

a citizen of the United States, residing at Center, in the county of -Oliver and State of North Dakota, have invented new and,

useful Improvements 'inLapp-ing Tools, of which the following is a specification.

' I The present invention has reference to a lapping tool especially desirable for tap-' ping bushings of aiitomobiles, and; of course, adaptable for tapping the openings in other articles. The primary object is the production of a lap-ping tool in which the tapping elements are brought against their work by centr1fugal force. 7, "is V V V A further object is to produce a lapping tool in which a plurality of loosely connected abrasive members are arranged upon a shank and which are spring influenced so as to arrange the same normally against the shank, so that the tool-may be read ly positioned in the opening whose wall it is 'to 'lap, the shank being attached to a drill or' similar implement whereby a rapid rotary motion is imparted thereto, and such centrifugal motion causing the abrasive members to be moved automatically away from the shank against the spring influenced means to engaging position with the wall of the opening to be lapped. I

A further object is the production of a lapping tool in which the abrasive members are influenced by a centrifugal force imparted to the member carrying the same, so that the said members will move away from the member to engage with the wall of the opening to be lapped, and also whereby walls of openings of various sizes may be properly lapped by the same instrument.

A further object is the production of a centrifu ally influenced lapping tool in which t e reaming or cut-ting elements are in'the nature of abrasive fabrics and in which the jaw members on which the said fabrics are arranged have simple means for retaining the same thereon, whereby such fabrics may be readily attached, and" readily removed when worn.

The foregoing objects, and others whlch will appear as the nature of theinvention is i better understood, may be accomplished by a construction, combination and operative arrangement of parts, such as is illustrated by the drawings.

In the drawings Figure 1 1's a side elevation 'of the im-' 'pnovement. Fig. 2 is a similar'view but showingthe jaws spread :as when the same are being revolved.

Fig. is a sectional view approximately on'the line 3-4) of .Fig. 1.

Fig. dis a detail view of one of the jaws,

illustrating the manner in which the abrasive cloth is clamped thereon.

My improvement is designed to have its shank received in the chuck of a drill so that a rapid .rotarymovement is imparted thereto.

The improvement includes a shank 1 that has one of its ends, that is. preferably round cross section and that has one of itsends formed with a tapered portion which is square or rectangular in cross section so as tobe receivedin the chuck of a drill or like implement which imparts. motion tothe shank. The opposite, or outer .end of the shank is :formed with what I will term a head 2. The head has an outer rounded portion, but is provided with equidistantly spaced pairs of ears 3, extending inwardly and arranged in parallelism with respect to the shank. The ears 3 are, however, spaced a suitable distance from the shank."

On the shank 1 there: is a slide in the naturei -of .a sleeve 4. The sleeve is provided with equidistantly spaced radially disposed ears 5. The ears 5 are arrangedin the same direction as are the ears of the head 2 The I ears 5 are of a length equaling that of the sleeve, and the opposed pairs of ears 5 have elongated slots 6 therethrou'gh.

On the shank, between the head 2 and the sleeve 4, is a comparatively light helical spring 7. i

Between each pair ofears 3 there is pivotally secured a link 8. Between each pair of ears 5 there is a link '9. Each of the links 9 has a transverse lug or pin 10.that is received in the slots 6 of the respective pairs of ears.

The numeral 11 designates what I will folded inwardly against said spring. I By grooving the inner faces of the jaws, the said jaws may be closely arranged against the spring, so that the same will not perceptibly project beyond the head 2 and the sleeve 4;. This permits of the ready insertion of the tool in a comparatively small opening whose wall is to be operated on. The jaws blocks ll have both of their ends bifurcated, and in these bifurcations are received the oppositely disposed links 8 and 9 which are pivoted to the jaws, as at 14:. The upper pivots and those arranged nearest the sleeve 4, provide means forsustaining on the sides of the jaws, fiat springs 15. On the outer rounded face and on the sides of each of the jaws there is arranged an abraby the fiat-springs 15, when the latter are swung against the sides of the jaws.

The operation of the device may be briefly described as follows: The jaws and links are bolted against the shanks, as illustrated in Fig. 1 of the drawings. The tool is then inserted through the bore of a bushing or like article to be lapped. The head 2 may rest on a suitable support. The drill, to which the shank l is attached, is then operated. Thejaws, are, as stated, in the nature of blocks, and therefore are weighted memsleeve.

hers. The rapid turning of. the shank will cause the jaws to swing outwardly from the shank against the pressure of the spring which is exerted between the head and the Thus the abrasive fabrics 16 will be brought against the wall of the opening to be reamed, and the said wall can be properly lapped in an easy, quick and espeditious manner. By the pivotal connection of the jaws with the links, the walls of angle openings as well as the walls of straight openings may be reamed with equal efliciency.

By providing the elongated slots- 6 in the outer or upper series of ears the jaws will swing on their links to bringthe abrasive surfaces thereof in engagement with the act on the work when the tool is held at slight angular positions with respect to the bushing operated on.v

The flat springs 15 are comparatively light, but are tightly secured on the blocks 11 so that the same cannot move laterally with respect to the blocks, and consequently, cannot project beyond the abrasive surface to interfere with the operation thereof.

his thought that the foregoing description, when taken in connection with the drawings, will fully set forth the construction and advantages of the improvement, as well as the operation thereof, without fur ther detailed description.

Having thus described the invention, what I claim, is I A lapping tool comprising a shank having its outer end rounded and .forming a head, equidistantly spaced pairs of ears carried by the head and extending inwardly,-the same being arranged in parallelism with respect to the shank, radially disposed links pivotally secured to said pairs of ears, a sleeve slidably mounted on the shank, 'equidistantly spaced radially disposed ears carried by the sleeve having-elongated slots the'rethrough.

a light helical spring between the head and sleeve, radially disposed links slidably mounted in the slots of said sleeve, weighted jaw members pivotally connected to the opposed links of the sleeve and head, and an abrasive element clamped to the outer face of the jaw members, substantially as described.

In testimony whereof I afiix my si nature. 

